Originally Posted by
mathe
I have US and UK passports. In the past, I've always handled this by showing the airline the US passport (in both directions) and showing immigration officials the passport they expect. However, it seems like the UK now uses advance passenger information, which I don't think was the case the last time I was there. What are the current best practices?
The US-UK dual-citizens with whom I travel give their US passport to the airline I the UK and in the US; and they flash their UK passport to the airline in the US only if asked about onward/return travel; and they give their US passport to US CBP on arrival to (and sometime departure from) the US; and they give their UK passport only to the UKBA on arrival in the UK.
Works flawlessly for my travel party to use only the US passport (except when dealing with UKBA) and merely flashing the UK passport to the airline outside of the UK
if the airline asks about onward/return travel.